scholarly journals Reproductive characteristics of mouse males are influenced by the mouse female pheromone 2,5-dimethylpyrazine in the C57BL/6 strain

2004 ◽  
Vol 2 (1) ◽  
pp. 44-49
Author(s):  
Eugene V Daev ◽  
Anna V Dukelskaya
Keyword(s):  
Somatic Cells ◽  
Sperm Head ◽  
Laboratory Mice ◽  
Reproductive Characteristics ◽  
Dominant Lethal ◽  
Female Pheromone ◽  
Dominant Lethals

The influence of the mouse female pheromone 2,5-dimethylpyrazine was studied on significant reproductive characteristics in C57BL/6 males. With this purpose the frequency of pheromonally induced sperm head abnormalities and dominant lethal frequency was analyzed. It is shown, that the level of different sperm head abnormalities increases significantly after exposure with the pheromones. Simultaneously with it the frequency of dominant lethals elevates significantly in the progeny of the treated males. Connection of the revealed effects with the destabilizing influence of the pheromone on the genome of dividing germ and somatic cells at laboratory mice is discussed

Reproductive characteristics of the african pygmy hedgehog, atelerix albiventris

Reproduction ◽  
2000 ◽  
pp. 143-150 ◽  
Author(s):  
JM Bedford ◽  
OB Mock ◽  
SK Nagdas ◽  
VP Winfrey ◽  
GE Olson
Keyword(s):  
Fallopian Tube ◽  
Zona Pellucida ◽  
Sperm Head ◽  
Reproductive Characteristics ◽  
Cumulus Oophorus ◽  
The Matrix ◽  
Main Components ◽  
Initial Binding ◽  
Structural Matrix

To obtain further perspective on reproduction and particularly gamete function among so-called primitive mammals presently grouped in the Order Insectivora, we have examined the African hedgehog, Atelerix albiventris, in light of unusual features reported in shrews and moles. Atelerix proves to share many but not all of the characteristics seen in these other insectivores. The penis of Atelerix has a 'snail-like' form, but lacks the surface spines common in insectivores and a number of other mammals. Hedgehog spermatozoa display an eccentric insertion of the tail on the sperm head, and they manifest the barbs on the perforatorium that, in shrews, probably effect the initial binding of the sperm head to the zona pellucida. As a possible correlate, the structural matrix of the hedgehog acrosome comprises only two main components, as judged by immunoblotting, rather than the complex of peptides seen in the matrix of some higher mammals. The Fallopian tube of Atelerix is relatively simple; it displays only minor differences in width and in the arborized epithelium between the isthmus and ampulla, and shows no evidence of the unusual sperm crypts that characterize the isthmus or ampulla, depending on the species, in shrews and moles. In common with other insectivores, Atelerix appears to be an induced ovulator, as judged by the ovulation of some 6-8 eggs by about 23 h after injection of hCG. The dense cumulus oophorus appeared to have little matrix, in keeping with the modest dimensions of the tubal ampulla and, while it was not quite as discrete as that of soricids, it did show the same insensitivity to 0.5% (w/v) ovine or bovine hyaluronidase.

scholarly journals The induction of dominant lethal mutations in rats and mice with triethylenemelamine (TEM)

1960 ◽  
Vol 1 (3) ◽  
pp. 381-392 ◽  
Author(s):  
A. J. Bateman
Keyword(s):  
Mutation Rate ◽  
X Rays ◽  
Type B ◽  
X Ray ◽  
Lethal Mutations ◽  
Dominant Lethal ◽  
Sensitive Stage ◽  
Dominant Lethal Mutations ◽  
Dominant Lethals ◽  
Rats And Mice

1. TEM resembles X-rays in inducing dominant lethal mutations in the sperm of rats and mice and sterilizing type B spermatogonia. Beyond this, however, there are several important differences.2. The relative ease with which TEM and X-rays affect sperm and spermatogonia varies greatly. The X-ray dose which produces 50% dominant lethals in sperm (500 rad) sterilizes spermatocytes and type B spermatogonia, and has such a drastic effect on type A spermatogonia that recovery of fertility is delayed for 2½ months. The TEM dose which produces the same mutation rate in sperm (0·1 mg./kg. rat) has no detectable effect on pre-meiotic stages. Even 1 mg./kg. only sterilizes the most sensitive stage, type B spermatogonia.3. Taking immature sperm as the standard, mature sperm are more sensitive to X-rays, but less sensitive to TEM, and early spermatids, the most sensitive stage to X-ray-induced dominant lethals, are highly resistant to TEM.4. Spermatocytes, in which X-rays yield a mutation rate equal to immaturesperm, are highly resistant to TEM.5. To produce the same mutation rate in immature sperm, mice require twice as much TEM as the rat in mg./kg., though approximately the same X-ray dose.6. In contrast to mid-stage rat spermatids, which are the most sensitive stage to TEM, mouse mid-stage spermatids are resistant.

scholarly journals Allelic Expression of Drosophila Protamines during Spermatogenesis

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Rachelle L. Kanippayoor ◽  
Amanda J. Moehring
Keyword(s):  
Somatic Cells ◽  
Male Meiosis ◽  
Sperm Head ◽  
Allelic Expression ◽  
Haploid Genome ◽  
Differential Allelic Expression ◽  
Selective Pressures ◽  
Single Allele ◽  
Reduced Space ◽  
Diploid Cells

In typical somatic cells, DNA is tightly organized by histones that are necessary for its proper packaging into the nucleus. In sexually-reproducing animals, the haploid product of male meiosis must be further condensed to fit within sperm heads, thus requiring an even greater degree of packaging. This is accomplished in most organisms by replacing histones with protamines, which allows DNA to be compacted into the reduced space. In mammals, protamines are produced after meiosis is complete and are transcribed by the single allele present in the haploid genome that is to be packaged into the sperm head. Here, we present our findings that protamine expression occurs from both alleles in diploid cells, rather than haploid cells, in two species of Drosophila. The differential allelic expression of protamines likely influences the selective pressures that shape their evolution.

scholarly journals EFFECTS OF DOSE ON THE INDUCTION OF DOMINANT-LETHAL MUTATIONS AND HERITABLE TRANSLOCATIONS WITH ETHYL METHANESULFONATE IN MALE MICE

Genetics ◽  
1974 ◽  
Vol 77 (4) ◽  
pp. 741-752
Author(s):  
W M Generoso ◽  
W L Russell ◽  
Sandra W Huff ◽  
Sandra K Stout ◽  
D G Gosslee
Keyword(s):  
Dose Response ◽  
Response Curve ◽  
Chromosome Breakage ◽  
Ethyl Methanesulfonate ◽  
Dose Response Curve ◽  
Male Mice ◽  
Lethal Mutations ◽  
Dominant Lethal ◽  
Dominant Lethal Mutations ◽  
Dominant Lethals

ABSTRACT Genetic damage by ethyl methanesulfonate (EMS) in male mice was measured at doses ranging from 50 to 300 mg/kg with dominant-lethal mutations and reciprocal translocations as endpoints. No appreciable increase in dominant-lethal mutations was detected following a dose of 100 mg/kg. Dominant lethals induced by EMS were convincingly detected only after a dose of 150 mg/kg, but in the translocation experiment an increase in the genetic effect was detectable at the 50 mg/kg dose. It is likely that dominant lethals had also been induced at the 50 and 100 mg/kg doses, but were not detected due to the relative insensitivity of the dominant%lethal procedure. Thus, for detection of low levels of EMS-induced chromosome breakage, translocations are a much more reliable endpoint than are dominant-lethal mutations. A procedure for large-scale screening of induced translocations is described.—The dominant-lethal dose-response curve, plotted on the basis of living embryos as a percentage of the control value, is clearly not linear as it is markedly concave downward. Similarly, the translocation dose-response curve showed a more rapid increase in the number of translocations with dose than would be expected on the basis of dose-square kinetics. It is clear for both of these endpoints that the effectiveness of EMS in inducing chromosome breakage is proportionately much lower at low doses.

Protamine-DNA interaction

1978 ◽  
Vol 36 (2) ◽  
pp. 200-201
Author(s):  
D.P. Bazett-Jones ◽  
F.P. Ottensmeyer
Keyword(s):  
Small Volume ◽  
Double Helix ◽  
Dna Interaction ◽  
Dark Field ◽  
Sperm Head ◽  
Nuclear Proteins ◽  
Field Electron Microscopy ◽  
Dark Field Electron ◽  
Dna Double Helix ◽  
Positively Charged

Dark field electron microscopy has been used for the study of the structure of individual macromolecules with a resolution to at least the 5Å level. The use of this technique has been extended to the investigation of structure of interacting molecules, particularly the interaction between DNA and fish protamine, a class of basic nuclear proteins of molecular weight 4,000 daltons.Protamine, which is synthesized during spermatogenesis, binds to chromatin, displaces the somatic histones and wraps up the DNA to fit into the small volume of the sperm head. It has been proposed that protamine, existing as an extended polypeptide, winds around the minor groove of the DNA double helix, with protamine's positively-charged arginines lining up with the negatively-charged phosphates of DNA. However, viewing protamine as an extended protein is inconsistent with the results obtained in our laboratory.

3-D examination of the cytoskeletal sheets of mammalian eggs

1992 ◽  
Vol 50 (1) ◽  
pp. 914-915
Author(s):  
Carolyn A. Larabell ◽  
David G. Capco ◽  
G. Ian Gallicano ◽  
Robert W. McGaughey ◽  
Karsten Dierksen ◽  
...  
Keyword(s):  
Actin Filaments ◽  
Somatic Cells ◽  
Freeze Fracture ◽  
Blastocyst Stage ◽  
Cell Cytoplasm ◽  
Planar Structures ◽  
Cytoskeletal Network ◽  
Entire Cell ◽  
Cytoskeletal Networks ◽  
Mammalian Eggs

Mammalian eggs and embryos contain an elaborate cytoskeletal network of “sheets” which are distributed throughout the entire cell cytoplasm. Cytoskeletal sheets are long, planar structures unlike the cytoskeletal networks typical of somatic cells (actin filaments, microtubules, and intermediate filaments), which are filamentous. These sheets are not found in mammalian somatic cells nor are they found in nonmammalian eggs or embryos. Evidence that they are, indeed, cytoskeletal in nature is derived from studies demonstrating that 1) the sheets are retained in the detergent-resistant cytoskeleton fraction; 2) there are no associated membranes (determined by freeze-fracture); and 3) the sheets dissociate into filaments at the blastocyst stage of embryogenesis. Embedment-free sections of hamster eggs viewed at 60 kV show sheets running across the egg cytoplasm (Fig. 1). Although this approach provides excellent global views of the sheets and their reorganization during development, the mechanism of image formation for embedment-free sections does not permit evaluation of the sheets at high resolution.

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